Preparation method and application of spherical nano bismuth oxide photocatalyst

Abstract

The invention provides a preparation method and an application of a spherical nano bismuth oxide photocatalyst, and relates to the field of novel catalysts. The preparation method comprises the following steps: dissolving bismuth-containing compounds and gluconic acid sodium in water, and adjusting the pH value to be 10-13 to obtain a mixed solution; putting the mixed solution in a high pressure reaction kettle, sealing, keeping for 18-24 hours at the temperature of 120-180 DEG C, and cooling to the room temperature; centrifuging the solution inside the high pressure reaction kettle, taking out precipitates and roasting after drying so as to obtain the spherical nano bismuth oxide photocatalyst. The invention further provides the spherical nano bismuth oxide photocatalyst prepared by adopting the method and an application of the spherical nano bismuth oxide photocatalyst to decomposition of catalytic organic pollutants. The preparation method is easy and convenient, low in cost and environmentally-friendly, and the productive rate reaches more than 80%. Spherical nano bismuth oxide is in nanoscale, uniform in particle size, relatively high in solar energy utilization rate and relatively high in quantum efficiency, and thus the spherical nano bismuth oxide has the relatively high photocatalytic activity, and can be applied to the decomposition of the catalytic organic pollutants.

Description

technical field

[0001] The invention relates to the field of novel catalysts, in particular to a preparation method and application of a nano-spherical bismuth oxide photocatalyst. Background technique

[0002] In recent years, the use of semiconductor nanoparticles photocatalytic method to control environmental pollution has been paid more and more attention. Theoretically, as long as the energy of the excitation light is greater than the band gap of the semiconductor, electrons and holes can be generated, and the semiconductor may be used as a photocatalyst. Due to various factors such as material cost, chemical stability, and photocorrosion resistance, efficient and practical materials still need further research. Common dual-element photocatalysts are mostly metal oxides or sulfides, among which the anatase phase TiO 2 There are more and more in-depth studies. But TiO 2 The wide band gap (3.2eV) can only absorb ultraviolet light with a wavelength less than 387nm, so ...

Examples

Embodiment 1

[0016] Under stirring conditions, add 1.5 mmol of bismuth nitrate pentahydrate to 35 mL of water, then add 4.5 mmol of sodium gluconate, stir well, adjust the pH of the solution to 10 with sodium hydroxide, and obtain a mixed solution. The mixed solution was put into an autoclave, sealed, and kept at 120° C. for 18 hours to carry out hydrothermal reaction. After the reaction, the autoclave was cooled to room temperature, the solution in the autoclave was centrifuged to collect the precipitate, washed with distilled water, dried at 50°C for 6 hours, and calcined at 400°C for 5h to obtain material 1. X-ray electron diffraction image from material 1 ( figure 1 ) It can be seen that material 1 is a pure phase of bismuth oxide. From the electron microscope topography of material 1 ( figure 2 ) It can be seen that bismuth oxide is nano-spherical with an average diameter of about 200nm.

Embodiment 2

[0018] Under stirring conditions, 1.5 mmol of bismuth nitrate pentahydrate was added to 35 mL of water, and then 6 mmol of sodium gluconate was added, stirred thoroughly, and the pH of the solution was adjusted to 11 with sodium hydroxide to obtain a mixed solution. Put the mixed solution into an autoclave, seal it, and keep it at 180°C for 24 hours to carry out hydrothermal reaction. After the reaction, the autoclave was cooled to room temperature, the solution in the autoclave was centrifuged to collect the precipitate, washed with distilled water, dried at 60°C for 4 hours, and then calcined at 500°C for 3h to obtain material 2. From the X-ray electron diffraction image of material 2, it can be seen that material 2 is a pure phase of bismuth oxide. From the electron microscope topography of material 2, it can be seen that bismuth oxide is in the shape of nanospheres with an average diameter of about 200 nm.

Embodiment 3

[0020] Under stirring conditions, 1.5 mmol of bismuth nitrate pentahydrate was added to 35 mL of water, and then 7.5 mmol of sodium gluconate was added, fully stirred, and the pH of the solution was adjusted to 13 with sodium hydroxide to obtain a mixed solution. Put the mixed solution into an autoclave, seal it, and keep it at 150°C for 22 hours to carry out hydrothermal reaction. After the reaction, the autoclave was cooled to room temperature, the solution in the autoclave was centrifuged to collect the precipitate, washed with distilled water, dried at 70°C for 3 hours, and then calcined at 600°C for 1 hour to obtain material 3. From the X-ray electron diffraction image of material 3, it can be seen that material 3 is a pure phase of bismuth oxide. From the electron microscope topography of material 3, it can be seen that bismuth oxide is in the shape of nanospheres with an average diameter of about 200 nm.

technical field

[0001] The invention relates to the field of novel catalysts, in particular to a preparation method and application of a nano-spherical bismuth oxide photocatalyst. Background technique

[0002] In recent years, the use of semiconductor nanoparticles photocatalytic method to control environmental pollution has been paid more and more attention. Theoretically, as long as the energy of the excitation light is greater than the band gap of the semiconductor, electrons and holes can be generated, and the semiconductor may be used as a photocatalyst. Due to various factors such as material cost, chemical stability, and photocorrosion resistance, efficient and practical materials still need further research. Common dual-element photocatalysts are mostly metal oxides or sulfides, among which the anatase phase TiO 2 There are more and more in-depth studies. But TiO 2 The wide band gap (3.2eV) can only absorb ultraviolet light with a wavelength less than 387nm, so ...

Examples

Embodiment 1

[0016] Under stirring conditions, add 1.5 mmol of bismuth nitrate pentahydrate to 35 mL of water, then add 4.5 mmol of sodium gluconate, stir well, adjust the pH of the solution to 10 with sodium hydroxide, and obtain a mixed solution. The mixed solution was put into an autoclave, sealed, and kept at 120° C. for 18 hours to carry out hydrothermal reaction. After the reaction, the autoclave was cooled to room temperature, the solution in the autoclave was centrifuged to collect the precipitate, washed with distilled water, dried at 50°C for 6 hours, and calcined at 400°C for 5h to obtain material 1. X-ray electron diffraction image from material 1 ( figure 1 ) It can be seen that material 1 is a pure phase of bismuth oxide. From the electron microscope topography of material 1 ( figure 2 ) It can be seen that bismuth oxide is nano-spherical with an average diameter of about 200nm.

Embodiment 2

[0018] Under stirring conditions, 1.5 mmol of bismuth nitrate pentahydrate was added to 35 mL of water, and then 6 mmol of sodium gluconate was added, stirred thoroughly, and the pH of the solution was adjusted to 11 with sodium hydroxide to obtain a mixed solution. Put the mixed solution into an autoclave, seal it, and keep it at 180°C for 24 hours to carry out hydrothermal reaction. After the reaction, the autoclave was cooled to room temperature, the solution in the autoclave was centrifuged to collect the precipitate, washed with distilled water, dried at 60°C for 4 hours, and then calcined at 500°C for 3h to obtain material 2. From the X-ray electron diffraction image of material 2, it can be seen that material 2 is a pure phase of bismuth oxide. From the electron microscope topography of material 2, it can be seen that bismuth oxide is in the shape of nanospheres with an average diameter of about 200 nm.

Embodiment 3

[0020] Under stirring conditions, 1.5 mmol of bismuth nitrate pentahydrate was added to 35 mL of water, and then 7.5 mmol of sodium gluconate was added, fully stirred, and the pH of the solution was adjusted to 13 with sodium hydroxide to obtain a mixed solution. Put the mixed solution into an autoclave, seal it, and keep it at 150°C for 22 hours to carry out hydrothermal reaction. After the reaction, the autoclave was cooled to room temperature, the solution in the autoclave was centrifuged to collect the precipitate, washed with distilled water, dried at 70°C for 3 hours, and then calcined at 600°C for 1 hour to obtain material 3. From the X-ray electron diffraction image of material 3, it can be seen that material 3 is a pure phase of bismuth oxide. From the electron microscope topography of material 3, it can be seen that bismuth oxide is in the shape of nanospheres with an average diameter of about 200 nm.

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